The present invention relates to continuous-rod cigarette-making machines, and more particularly it concerns improvements in the rod-breaking devices for such machines.
In a continuous-rod cigarette-making machine, a moving cigarette rod is formed by wrapping a moving cigarette paper web about a tobacco filler in a rod-forming mechanism, the continuous rod then passing to a cutter mechanism it is severed into individual cigarette lengths. Normally, the rod-forming mechanism includes a paster which applies adhesive to one edge of the paper web, said edge then being folded to overlap the other edge of the web and adhere thereto, and a heater to seal the overlapping adhering edges.
When the machine is started, the rod issuing from the rod-forming mechanism is initially unsuitable for producing satisfactory cigarettes, because it may be not correctly sealed or contain insufficient tobacco filler. Therefore, at each starting operation, the initial portion of the freshly produced rod is deflected to a waste receptacle and when the rod produced becomes satisfactory, it is broken to separate the suitable rod being produced from the rod which has been deflected to the waste receptacle, and allow the leading end of the rod behind the break to proceed along the normal straight path to the cutter mechanism.
Moreover, it has been also found desirable to break the continuous cigarette rod whenever the machine is stopped. A segment of the rod remains, after this breaking, in the guide members guiding to the cutter mechanism, or in the detector unit (usually arranged prior to the cutter mechanism) in which the specific weight of the tobacco filler of the cigarette rod is sensed. The said rod segment must be pneumatically expelled, in order to permit to start again the machine.
According to British Pat. No. 1,547,763, it has been proposed a rod-breaking device comprising a guide member adapted to be moved across the path of the rod, in which movement of said guide member in one direction serves to break the rod, whereafter the guide member stops in such a position as to deflect the following rod out of the normal straight path: the above operation is required upon stopping of the machine and (after starting of the machine) for the disposal of the initially unsuitable rod. The movement of the guide member in the opposite direction serves to break the rod and to bring the said guide member to a position outside the normal straight path of the rod: this latter operation is required for the feeding of the rod to the cutter mechanism or to the detector mechanism, after having reached satisfactory condition of the rod being produced. The breaking of the rod upon stopping of the machine is obtained by cooperation of the guide member which, during its movement across the path of the moving rod, forces the moving rod against a fixed abutment, thus deflecting and breaking it.
The above mentioned rod-breaking device presents the drawback that, whenever the machine is stopped, the breaking of the rod, subsequent to the cooperation of the moving guide member and of the fixed abutment, leads to some deformation of the rod in the portion immediately downstream of the break point. This deformed portion constitutes the tail portion of the rod segment which remains inserted in the guide members which lead to the cutter mechanism, or in the tubular guide member of the detector mechanism for sensing the specific weight of the tobacco filler. Usually, the said rod segment is expelled from the said guide members by pneumatic means, such as air blows. The presence of the said deformed tail portion may lead to jamming of the rod segment in the guide members, which constitutes an obstacle to the pneumatic expulsion of the rod segment itself. In consideration of the fact that the starting of the machine is subject to the condition of the previous removal of any rod segment, it is of the greatest importance to provide a rod breaking device which, upon stopping of the machine, provides to the expulsion of any deformed portion of the tail section of the rod after the breaking of the rod itself.
According to the present invention, there is provided a rod breaking device of the type above referred to, characterized by the fact that a transverse blade is operatively associated with the movable guide member which breaks the rod, said blade being movable across the normal straight path of the cigarette rod, close to the inlet of the processing unit (cutter mechanism or weight detector unit), in such a manner that upon movement of the guide member to break the rod at the stopping of the machine, the said transverse blade moves concurrently with the guide member and cuts with a clean cut the tail portion of the cigarette rod entering the inlet of the processing unit, thus eliminating the deformed segment of rod delimited downstream by the said cut effected by the blade, and upstream by the break effected by the cooperation of the guide member with the fixed abutment.
According to a preferred embodiment, the said transverse blade is secured on the said guide member, and the cutting edge of the blade is in substantial alignment with the portion of the deflecting guide which cooperates with the fixed abutment for breaking the rod, so that the breaking of the rod effected by the cooperation of the moving guide member with the fixed abutment, and the cutting of the rod effected by the blade, take place simultaneously and are both controlled by the single movement of the guide member across the normal straight path of the continuous rod.
The above and other features of the invention, and the advantages deriving therefrom, will appear evident from the following description of a preferred embodiment, made with reference to the Figures of the attached drawings.